System Mass Ratio Research Articles

Construction and characterization of pickering emulsion stabilized by amphoteric microgel and its application in cotton fabric

Studies with regard to how to obtain superhydrophobic properties by directly coating emulsified silicone oil onto the surface of cotton fabric have always been a hot topic in the field of textiles. In this paper, an amphoteric microgel with thermo- and pH-responsive ability was synthesized. Subsequently, a series of Poly(methylhydrosiloxane) (PMHS) /water emulsions were prepared by using these amphoteric microgels as a Pickering emulsifier. When the PMHS/water system's mass ratio was 5/5 and the microgel content was kept at 2.0 wt%, this emulsion showed good stability allowing the PMHS parts to be dispersed uniformly in aqueous solution. The optical microscopy showed the emulsion's particle size was in a range from 5 to 20 μm and the stability test confirmed that no stratification occurred when this emulsion was subjected to 3000 rpm for 30 min. By using this emulsion as a post-treatment reagent, cotton fabrics with different yarn counts can obtain a water contact angle as high as 150o, which is about 25 % higher than commercial emulsifiers. Furthermore, this cotton fabric can hold superhydrophobicity after 50 rubbing cycles and 10 peel-off cycles. The development of this work provides a new direction for the study of the application of microgels.

Orbital evolution of binaries in circumbinary discs

ABSTRACT We present the to-date largest parameter space exploration of binaries in circumbinary discs (CBDs), deriving orbital evolution prescriptions for eccentric, unequal mass binaries from our suite of hydrodynamic simulations. In all cases, binary eccentricities evolve towards steady state values that increase with mass ratio, and saturate at an equilibrium eccentricity eb,eq ∼ 0.5 in the large mass ratio regime, in line with resonant theory. For binaries accreting at their combined Eddington limit, a steady state eccentricity can be achieved within a few megayears. Once at their steady state eccentricities, binaries with qb ≳ 0.3 evolve towards coalescence, while lower mass ratio systems expand due to CBD torques. We discuss implications for population studies of massive black hole binaries, protostars in binary systems, and post-common envelope binaries observed by ground-based gravitational wave detectors.

Oscillation control and drag reduction for a low mass ratio cylinder with double splitter plates

A flow-induced vibration (FIV) investigation to realize oscillation control and drag reduction for an elastically mounted cylinder with double splitter plates (DSPs) attached was undertaken in a water tunnel at Reynolds number of 1100-7700. The length of the splitter plate is in a range of L∗ = 0-2.0 (L∗ = L/D, L is the plate length, D is the cylinder diameter). The intersection angle between two plates, δ, varies from 0°−90°. The dependence of oscillation characteristics, vortex evolution and drag force coefficients on L∗−δ is illustrated in detail. Four oscillation patterns are identified: VIV, combined VIV-galloping, separated VIV-galloping, and suppressed patterns. Under similar structural parameters, the device can perform well both in high and low mass ratio systems, which implies that mass ratio has little effect on the suppression efficiency of DSPs. Besides, the drag force coefficient is proportional to the vertical span of the plate tips, Lp, and the empirical formula is yielded. For Lp<1.3, both oscillation suppression and drag reduction can be attained. Flow visualization shows that the fixed separation points of shear layers resulting in the destructive vortex shedding in the downstream, which is responsible for the wake-stabilization in the downstream and FIV suppression.

Analysis of dual band and survey photometry of two low mass ratio contact binary systems

The study presents photometric analysis of the completely eclipsing contact binary systems TYC 8351-1081-1 and ASAS J210406-0522.3. TYC 8351-1081-1 is an extremely low mass ratio (q=0.086) system with high degree of contact (f=0.66) while ASAS J210406-0522.3 is found to be in marginal contact (f=0.08) with a relatively low mass ratio of 0.272. There is good thermal contact in both systems with only a small difference in the temperature of the components. The systems have been observed by a number sky surveys over the past 20 years. We compare the light curve solutions from up to three of these surveys and find that survey photometric data manually analysed is robust and yields results comparable to dedicated ground based photometry. There is evidence of significant luminosity transfer from the primary to the secondary, on the order of 0.5LJ for TYC 8351-1081-1 and 0.06LJ for ASAS J210406-0522.3. There appears to be no change in period of either system over the past 20 years and theoretical angular momentum loss is below current measurement threshold in both cases. We also show that the mass ratio and separation are well above the theoretical values for orbital instability in both cases. As would be expected, the density of the secondary components is significantly higher relative to the primary.

Red supergiant stars in binary systems. I. Identification and characterisation in the small magellanic cloud from the UVIT ultraviolet imaging survey

Abstract We aim to identify and characterise binary systems containing red supergiant (RSG) stars in the Small Magellanic Cloud (SMC) using a newly available ultraviolet (UV) point source catalogue obtained using the Ultraviolet Imaging Telescope (UVIT) on board AstroSat. We select a sample of 560 SMC RSGs based on photometric and spectroscopic observations at optical wavelengths and cross-match this with the far-UV point source catalogue using the UVIT F172M filter, finding 88 matches down to mF172M = 20.3 ABmag, which we interpret as hot companions to the RSGs. Stellar parameters (luminosities, effective temperatures and masses) for both components in all 88 binary systems are determined and we find mass distributions in the ranges 6.1 &amp;lt; M/M⊙ &amp;lt; 22.3 for RSGs and 3.7 &amp;lt;M/M⊙ &amp;lt; 15.6 for their companions. The most massive RSG binary system in the SMC has a combined mass of 32 ± 4 M⊙, with a mass ratio (q) of 0.92. By simulating observing biases, we find an intrinsic multipliciy fraction of $18.8\, \pm \, 1.5\, {{\ \rm per\ cent}}$ for mass ratios in the range 0.3 &amp;lt; q &amp;lt; 1.0 and orbital periods approximately in the range $3 &amp;lt; \log P [\rm days] &amp;lt; 8$. By comparing our results with those of a similar mass on the main-sequence, we determine the fraction of single stars to be ∼20 per cent and argue that the orbital period distribution declines rapidly beyond log P ∼ 3.5. We study the mass-ratio distribution of RSG binary systems and find that a uniform distribution best describes the data below 14 M⊙. Above 15 M⊙, we find a lack of high mass-ratio systems.

Learning orbital dynamics of binary black hole systems from gravitational wave measurements

We introduce a gravitational waveform inversion strategy that discovers mechanical models of binary black hole (BBH) systems. We show that only a single time series of (possibly noisy) waveform data is necessary to construct the equations of motion for a BBH system. Starting with a class of universal differential equations parameterized by feed-forward neural networks, our strategy involves the construction of a space of plausible mechanical models and a physics-informed constrained optimization within that space to minimize the waveform error. We apply our method to various BBH systems including extreme and comparable mass ratio systems in eccentric and noneccentric orbits. We show that the resulting differential equations apply to time durations longer than the training interval, and relativistic effects, such as perihelion precession, radiation reaction, and orbital plunge, are automatically accounted for. The methods outlined here provide a data-driven approach to studying the dynamics of binary black hole systems.

Climbing up the memory staircase: Equatorial zoom-whirl orbits

The nonlinear, or null gravitational memory effect for zoom-whirl orbits around fast spinning Kerr black holes for extreme mass ratio systems has a staircase structure. The latter is characterized by a periodic fast increase in the memory during the whirl phases of the orbit, and near constant levels when the orbit is near apoapsis. We study the contribution of different spherical harmonic modes to this effect, and discuss the relative importance thereof. Because the hereditary memory effect increases in magnitude linearly in the number of periapsis passages on a dynamical time scale, while the oscillatory parent gravitational waves are sourced by an orbit that evolves on a much longer radiation reaction time scale, the magnitude of the former relative to the latter increases with time. We also consider orphan memory and the memory effect for extreme mass ratio inspirals. We then discuss the prospect of detection with the Laser Interferometer Space Antenna (LISA).

Photometric study of three contact binary systems

The first complete light curves of two eclipsing binaries in Camelopardalis, NX Cam and V584 Cam, are here presented together with the new observations of the system NSVS 2643686 obtained in 2014. The light curves were modelled using the latest version of the Wilson-Devinney code. Our results show that all the three systems have an extreme mass ratio q < 0.2, two of them, NX Cam and NSVS 2643686, having the fill-out f > 50%, belong to the class of the so called Deep Low Mass Ratio systems (DLMR) but show different physical characteristics. The two above systems are totally eclipsed binaries with the duration of the secondary eclipse of 87 min for NX Cam and 51 min for NSVS 2643686. The other system, V584 Cam, shows a middle fill-out value of f = 33% and low inclination. Using our Times of Minima (ToM) derived from the observations as well as those found in the literature, the ephemerides of the three systems are here revised. The absolute dimensions are estimated and, from statistical diagram, it is found that all the components of the systems follow the general pattern of the well known W UMa contact binaries.

The structure of the co-orbital stable regions as a function of the mass ratio

ABSTRACT Although the search for extrasolar co-orbital bodies has not had success so far, it is believed that they must be as common as they are in the Solar system. Co-orbital systems have been widely studied, and there are several works on stability and even on formation. However, for the size and location of the stable regions, authors usually describe their results but do not provide a way to find them without numerical simulations, and, in most cases, the mass ratio value range is small. In this work, we study the structure of co-orbital stable regions for a wide range of mass ratio systems and build empirical equations to describe them. It allows estimating the size and location of co-orbital stable regions from a few system parameters. Thousands of massless particles were distributed in the co-orbital region of a massive secondary body and numerically simulated for a wide range of mass ratios (μ) adopting the planar circular restricted three-body problem. The results show that the upper limit of horseshoe regions is between 9.539 × 10−4 &amp;lt; μ &amp;lt; 1.192 × 10−3, which corresponds to a minimum angular distance from the secondary body to the separatrix of between 27.239º and 27.802º. We also found that the limit to existence of stability in the co-orbital region is about μ = 2.3313 × 10−2, much smaller than the value predicted by the linear theory. Polynomial functions to describe the stable region parameters were found, and they represent estimates of the angular and radial widths of the co-orbital stable regions for any system with 9.547 × 10−5 ≤ μ ≤ 2.331 × 10−2.

Investigation of near-contact semi-detached binary WUMi through observations and evolutionary models

W UMi is a near contact, semi-detached, double-lined eclipsing binary star with an orbital period of 1.7 d. Simultaneous analysis of new BV R multi-color light curves and radial velocity data yields the main astrophysical parameters of the binary and its component stars. We determined mass and radius to be M1 = 3.22 ± 0.08 M⊙, R1 = 3.63 ± 0.04 R⊙ for the primary star and M2 = 1.44 ± 0.05 M⊙, R2 = 3.09 ± 0.03 R⊙ for the secondary star. Based on analysis of mid-eclipse times, variation in the orbital period is represented by a cyclic term and a downward parabola. Mass loss from the system is suggested for a secular decrease (−0.02 s yr−1) in the period. Both the mechanisms of a hypothetical tertiary star orbiting around W UMi and the surface magnetic activity of the less massive cooler companion were used to interpret periodic changes. Observational parameters were found to be consistent with binary stellar evolution models produced in the non-conservative approach of MESA at a higher metallicity than the Sun and an age of about 400 Myr for the system. Evidence that the system is rich in metal was obtained from spectral and kinematic analysis as well as evolution models. W UMi, a high mass ratio system compared to classical semi-detached binaries, is an important example since it is estimated from binary evolutionary models that the system may reach its contact phase in a short time interval.

On the vortex-induced vibration of a low mass ratio circular cylinder near a planar boundary

Vortex-induced vibration of a circular cylinder near a plane boundary has been investigated experimentally for 2,500≤ReD≤10,000, 3.0≤U*≤12.0, 0.3≤S*≤8, and m*=5.3, where ReD is the Reynolds number based on cylinder diameter, U* is the reduced velocity, S* is the gap distance between the planar wall and the cylinder, and m* is the system's mass ratio. The experimental data includes simultaneous amplitude response and wake measurements via time-resolved planar particle image velocimetry (PIV). From experimental raw data, frequency content of the oscillations as well as wake velocity and vorticity fields are analyzed. A new vortex shedding flow regime map is proposed, illustrating dominant vortex shedding patterns in the wake across the investigated non-dimensional parameter space. The quantitative relationship between the cylinder's motion and instantaneous vortex dynamics is shown.

Exciting black hole modes via misaligned coalescences. I. Inspiral, transition, and plunge trajectories using a generalized Ori-Thorne procedure

The last gravitational waves emitted in the coalescence of two black holes are quasi-normal ringing modes of the merged remnant. In general relativity, the mass and the spin of the remnant black hole uniquely determine the frequency and damping time of each radiated mode. The amplitudes of these modes are determined by the mass ratio of the system and the geometry of the coalescence. This paper is part I of an analysis that aims to compute the "excitation factors" associated with misaligned binary black hole coalescence. To simplify the analysis, we consider a large mass ratio system consisting of a non-spinning body of mass $\mu$ that inspirals on a quasi-circular trajectory into a Kerr black hole of mass $M$ and spin parameter $a$, with $\mu/M \ll 1$. Our goal is to understand how different modes are excited as a function of the black hole spin $a$ and an angle $I$ which characterizes the misalignment of the orbit with the black hole's spin axis. Though the large mass ratio limit does not describe the binaries that are being observed by gravitational-wave detectors today, this limit makes it possible to quickly and easily explore the binary parameter space, and to develop insight into how the system's late ringing waves depend on the binary's geometry. In this first analysis, we develop the worldline which the small body follows as it inspirals and then plunges into the large black hole. Our analysis generalizes earlier work by Ori and Thorne to describe how a non-equatorial circular inspiral transitions into a plunging trajectory that falls into the black hole. The worldlines which we develop here are used in part II as input to a time-domain black hole perturbation solver. This solver computes the gravitational waves generated by such inspirals and plunges, making it possible to characterize the modes which the coalescence excites.

Effect of oil–paper–pressboard mass ratio on furfural content in transformer oil

Furfural content in oil is widely accepted as an effective parameter to mirror aging of insulation paper. However, pressboards are also abundant in transformers, which are always neglected in furfural analysis. Different masses of insulation paper and pressboard produce different amounts of furfural during the aging process. Thus, the furfural content in oil may differ in systems with different oil-paper-pressboard mass ratios. To address this problem, accelerated thermal aging experiments and furfural equilibrium experiments with different oil-paper-pressboard mass ratio systems were conducted under laboratory conditions. Furfural contents in oil, paper, and pressboard were measured. In a simplified oil-paper system, the furfural content in oil differs in systems with different oil-paper mass ratios. Further analysis shows the furfural amount produced by 1 g insulation paper is the same with good repeatability in groups with different mass ratios. Different oil-paper mass ratios change the distribution coefficient of furfural between oil and paper, and an increase in the mass of insulation paper leads to more furfural remaining in the insulation paper. The pressboards in field transformers produce little furfural during the aging process, but absorb part of the furfural from oil, which decreases the furfural content in oil. Therefore, more pressboard in an oil-paper-pressboard system indicates lower furfural content in oil. An increase in insulation paper in the oil-paper-pressboard system causes a decrease in the effect of pressboard on furfural content in oil.

Levels of Shading and Reflective Material in Benches for Schizolobium amazonicum Seedlings

High quality forest seedlings are essential for the implementation of a commercial forest system, and it is therefore necessary to study their development in different environments, seeking to identify the most favorable environment for their production. In view of the above, the purpose of this essay was to evaluate the production of quamwood seedlings in different environments and workbenches with reflective material. The study was conducted at the State University of Mato Grosso do Sul-Cassil&amp;acirc;ndia-MS from August to November 2017, in a completely randomized design within each environment and the environments compared by the joint analysis of the data. At the opportunity, produced quamwood seedlings under shade levels of 0% (full sun), 30% under sombrite, 35% under thermo-reflective screen and the agricultural greenhouse with thermo-reflective screen under the film with 42/50% shading. In the interior of each environment the seedlings were placed on cultivation benches with reflective material (aluminum paper) and without reflective material. The environments were compared by the joint analysis, and the results of molt height and lap diameter were measured at 30, 55 and 72 days after transplanting. The experiment was completed at 72 days after transplanting and the destructive analysis of the seedlings was performed, subjecting them to drying in a forced ventilation oven until reaching a constant dry mass. Based on the results obtained, the total dry mass, height and diameter ratio, root dry mass ratio and dry mass root system, absolute growth rate and Dickson quality index were calculated. The protected environments were favorable to the formation of paric&amp;aacute; seedlings. The environment in full sun formed small, but more rustic seedlings. The use of reflective material had a positive effect only in the plastic coverage environment with 42/50% shading screen.

Synthesis and application of aqueous stomach aminoalkyl methacrylate copolymer

A series of stomach cationic aminoalkyl methacrylate copolymer emulsions containing large number of tertiary amino groups in molecular side chain were prepared throughl emulsion polymerization, which take dimethylaminoethyl methacrylate, methyl methacrylate and butyl methacrylate as main raw materials. The The properties of the emulsions were characterized by Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). And effects of monomer mass ratio and emulsifier system on the properties of emulsions polymerization were also discussed. The results showed that the emulsion performance was stable when the amount of emulsifier was 4.5wt% taking cationic and non-ionic composite emulsifier as emulsifying system. At the same time, it has excellent moisture resistance and stable performance when used in pharmaceutical coating materials.

Properties of the single Jovian planet population and the pursuit of Solar system analogues

While the number of exoplanets discovered continues to increase at a rapid rate, we are still to discover any system that truly resembles the Solar system. Existing and near future surveys will likely continue this trend of rapid discovery. To see if these systems are Solar system analogues, we will need to efficiently allocate resources to carry out intensive follow-up observations. We seek to uncover the properties and trends across systems that indicate how much of the habitable zone is stable in each system to provide focus for planet hunters. We study the dynamics of all known single Jovian planetary systems, to assess the dynamical stability of the habitable zone around their host stars. We perform a suite of simulations of all systems where the Jovian planet will interact gravitationally with the habitable zone, and broadly classify these systems. Besides the system's mass ratio (Mpl/Mstar), and the Jovian planet's semi-major axis (apl) and eccentricity (epl), we find that there are no underlying system properties which are observable that indicate the potential for planets to survive within the system's habitable zone. We use Mpl/Mstar, apl and epl to generate a parameter space over which the unstable systems cluster, thus allowing us to predict which systems to exclude from future observational or numerical searches for habitable exoplanets. We also provide a candidate list of 20 systems that have completely stable habitable zones and Jovian planets orbiting beyond the habitable zone as potential first order Solar system analogues.

Dynamical tides in general relativity: Effective action and effective-one-body Hamiltonian

Tidal effects have an important impact on the late inspiral of compact binary systems containing neutron stars. Most current models of tidal deformations of neutron stars assume that the tidal bulge is directly related to the tidal field generated by the companion, with a constant response coefficient. However, if the orbital motion approaches a resonance with one of the internal modes of the neutron star, this adiabatic description of tidal effects starts to break down, and the tides become dynamical. In this paper, we consider dynamical tides in general relativity due to the quadrupolar fundamental oscillation mode of a neutron star. We devise a description of the effects of the neutron star's finite size on the orbital dynamics based on an effective point-particle action augmented by dynamical quadrupolar degrees of freedom. We analyze the post-Newtonian and test-particle approximations of this model and incorporate the results into an effective-one-body Hamiltonian. This enables us to extend the description of dynamical tides over the entire inspiral. We demonstrate that dynamical tides give a significant enhancement of matter effects compared to adiabatic tides, at least for neutron stars with large radii and for low mass-ratio systems, and should therefore be included in accurate models for gravitational-wave data analysis.

Photometric solution and period analysis of the contact binary system AH Cnc

Photometric observations of AH Cnc, a W UMa-type system in the open cluster M67, were carried out by using the 50BiN telescope. About 100 h of time-series B- and V -band data were taken, based on which eight new times of light minima were determined. By applying the Wilson-Devinney method, the light curves were modeled and a revised photometric solution of the binary system was derived. We confirmed that AH Cnc is a deep contact (f = 51%), low mass-ratio (q = 0.156) system. Adopting the distance modulus derived from study of the host cluster, we have re-calculated the physical parameters of the binary system, namely the masses and radii. The masses and radii of the two components were estimated to be respectively 1.188(±0.061) M⊙, 1.332(±0.063) R⊙ for the primary component and 0.185(±0.032) M⊙, 0.592(±0.051) R⊙ for the secondary. By adding the newly derived minimum timings to all the available data, the period variations of AH Cnc were studied. This shows that the orbital period of the binary is continuously increasing at a rate of dp/dt = 4.29 × 10−10 d yr−1. In addition to the long-term period increase, a cyclic variation with a period of 35.26 yr was determined, which could be attributed to an unresolved tertiary component of the system.

Study on the formation and rheological properties of sucrose stearate lamellar liquid crystals

ABSTRACTThe phase diagrams of S1570–Brij 97/oleic acid/water system at two different S1570/Brij 97 mass ratios of 1/1 (system S) and 7/3 (system P) were determined at 37°C, respectively. The microstructures and rheological properties of liquid crystals at constant surfactants/water mass ratio of 1/1 were studied with increase in oil content. Small-angle x-ray scattering measurements showed that system S exhibited a typical lamellar liquid crystals and the repeat distance (d) decreased as oil content increased. While for system P, two couples of scattering peaks were observed when oil content reached 28 wt%. This indicated that adding oil content may give rise to a multilamellar structures in the higher S1570/Brij 97 mass ratio system. The rheological tests indicated that a transition from elastic gel-like properties to viscoelastic liquid-like properties appeared in both system S and P when oil content reached 20 wt%, corresponding to the polarizing optical microscopy textures changing from oily streak to cruciate flower. This supplies a way to adjust structure, rheological properties, and even phase transition by altering the S1570/Brij 97 mass ratio and oleic acid content in system.

Matching asteroid population characteristics with a model constructed from the YORP-induced rotational fission hypothesis

From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis is consistent with the observed population statistics of small asteroids in the main belt including binaries and contact binaries. These conclusions rest on the asteroid rotation model of Marzari et al. ([2011]Icarus, 214, 622–631), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis, described in detail within, and the binary evolution model of Jacobson et al. ([2011a] Icarus, 214, 161–178) and Jacobson et al. ([2011b] The Astrophysical Journal Letters, 736, L19). Our complete asteroid population evolution model is highly constrained by these and other previous works, and therefore it has only two significant free parameters: the ratio of low to high mass ratio binaries formed after rotational fission events and the mean strength of the binary YORP (BYORP) effect.We successfully reproduce characteristic statistics of the small asteroid population: the binary fraction, the fast binary fraction, steady-state mass ratio fraction and the contact binary fraction. We find that in order for the model to best match observations, rotational fission produces high mass ratio (> 0.2) binary components with four to eight times the frequency as low mass ratio (<0.2) components, where the mass ratio is the mass of the secondary component divided by the mass of the primary component. This is consistent with post-rotational fission binary system mass ratio being drawn from either a flat or a positive and shallow distribution, since the high mass ratio bin is four times the size of the low mass ratio bin; this is in contrast to the observed steady-state binary mass ratio, which has a negative and steep distribution. This can be understood in the context of the BYORP-tidal equilibrium hypothesis, which predicts that low mass ratio binaries survive for a significantly longer period of time than high mass ratio systems. We also find that the mean of the log-normal BYORP coefficient distribution μB≳10−2, which is consistent with estimates from shape modeling (McMahon and Scheeres, 2012a).